Please see the original post - I am in no way recommending to go for every Oracle VM workload to this monster VM - in fact a best practice is to divide whenever possible. But if you can't go this way - that's true in our case - read on for more details I was able to capture.
Good news: customer is running benchmark test on a system with 32 cores (HP B660 with 4x4650 with 8 cores) and 768GB RAM. A monster VM scales fine up to 28vCPUs now and only drops to performance of 24 cores with 32vCPUs. We haven't run yet the application, but it looks like that in this case Hyperthreading (HT) on the previous machine didn't work well. We are looking for the vSphere 5.5 release to try advanced features as well to apply best practices for Oracle tuning on a VMware VM. As posted earlier the document on VMware's Oracle landing page seems to be outdated (2011) here are more recent hints and tips.In the scenario we run Oracle 188.8.131.52 at this point.
These are the key topics we identified in our situation - you might want to visit the following resources that provide further detail and we were looking at: